A headlight of this type is known from European Patent Application No. 0 129 922. The reflector has a cylindrical edge that parallels the direction the light emerges in, and the outside of the edge has a continuous groove around it that extends in a plane perpendicular to the optical axis. A sealing ring is snapped into the groove. The mount for the reflector also has a cylindrical edge that faces the reflector, and the cylindrical edge of the reflector is inserted into the cylindrical edge of the mount, with the sealing ring forced against the inner surface of the cylindrical edge of the mount, sealing the inside of the headlight off from the atmosphere. Two tabs are shaped onto the cylindrical edge of the reflector and extend parallel to the direction the light emerges in, with their free ends constituting two bearings in conjunction with the mount, which is annular. An adjustment device inserted between the mount and the reflector is activated to pivot the reflector around the axis of the bearings, which is horizontal when the headlight is installed. When the reflector is pivoted around its horizontal axis, either the upper or lower section of the sealing ring is either compressed or released very powerfully throughout its range of reslience because the axis is at a distance from a plane that is perpendicular to the optical axis and that the sealing ring lies in. This limits the range of adjustment of the reflector to a considerable extent and, as the rubber that the ring is made out of ages, the seal between the reflector and the mount loses its effectiveness. Furthermore, the sealing ring in the groove around the edge of the reflector rubs against the inside of the mount when the reflector pivots. To ensure that the reflector will pivot freely and smoothly, the sealing ring must be made out of soft rubber. Frequent pivoting of the sealing ring impairs the seal between the reflector and the mount because a sealing ring of soft rubber is very sensitive to wear. Although a hard-rubber ring is a lot less sensitive to wear, it must rest against the mount with a lot more force to maintain a satisfactory seal between the reflector and mount, and the reflector requires a lot more effort to adjust.
The axis that the reflector pivots on in another headlight, illustrated schematically in the drawing in European Patent Application No. 0 129 922, extends in the same plane that the sealing ring extends in when it is snapped over the reflector.